Influence of grip types and intensities on force-decreasing curves and physiological responses during sustained muscle contractions

Abstract

This study aimed to examine relationships between force outputs during sustained isometric grips (SIG) and intermittent repeated grips (IRG) with three relative target forces (50%, 75%, and 100% MVC), and subjective muscle-fatigue sensation (SMS) and blood lactate (La) during and after gripping tests. Ten young males performed sustained grip tests with 2 grip types and 3 target forces for 6 min. La and maximal grip strength were measured before, just after and 4 min and 7 min after each grip test. SMS of the forearm was measured every 30 s during and after each grip test. The relationships of average grip force in every 30 s between SIG and IRG were not good. The La value after IRG tests with 75% and 100% MVCs tended to be higher than that in the other conditions. The tendency for decline differs with grip type, intensity (target forces) and the force outputs among the conditions. The muscle fatigue level in the SIG and IRG may differ largely even when using the same target force. Although the SIG imposes a larger burden on subjects than the IRG, La after gripping work is lower.